<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .font-size{
      font-size: 2rem;
    }
    .font-size{
      border: 1px solid red;
    }
  </style>
</head>
<body>
<div class="font-size">
  <p>Smaple Text</p>
  <div class="font-size">
    <p>Smaple Text</p>
    <div class="font-size">
      <p>Smaple Text</p>
    </div>
  </div>
</div>
</body>
</html>
